TSK · Numbers 18:16

This they shall give, every one that passeth over unto them that are numbered: half a shekel after the shekel of the sanctuary (the shekel is twenty gerahs), half a shekel for an offering to Jehovah.

And all thy estimations shall be according to the shekel of the sanctuary: twenty gerahs shall be the shekel.

And the shekel shall be twenty gerahs; twenty shekels, five and twenty shekels, fifteen shekels, shall be your maneh.